From debster

1c. sour cream
1c. mayo
1 med. onion, chopped
1/2 stick butter
2T. chopped fresh parsley
1/2t. Tabasco
dash of Worcestershire and garlic powder
salt and pepper to taste 

Sauté onion in butter until tender. Mix all together and chill for several hours.
This is quite good served hot also. You can broil it with cheese on top. It's fabulous and makes a great presentation!